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#15596
Let's improve the default workings of electric-indent-mode.
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Message #11 received at 15596 <at> debbugs.gnu.org (full text, mbox):
Hello, Stefan.
On Sat, Oct 12, 2013 at 12:35:46PM -0400, Stefan Monnier wrote:
> > At the moment, it is (rather crudely) just nil or t, globally for all
> > modes and all buffers. This is unsatisfactory, as it makes it difficult
> > to {en,dis}able e-i-m for a single mode, and for a single buffer. An
> > example of when you might want to do the latter is thus: one has an
> > isolated file.c (or section therewithin) whose indentation style does not
> > conform to project norms, and one does not wish to reindent the file
> > wholesale. Electric indentation makes editing such a file inconvenient,
> > hence the need for the ability readily to switch it off (currently
> > available in CC Mode with C-c C-l).
> Currently it's easyish for the user to do
> (add-hook 'blabla-hook
> (lambda () (setq-local electric-indent-mode nil)))
> Or to set electric-indent-mode to nil in the file variables.
These are surely bad ideas. `electric-indent-mode' is a global mode, so
creating buffer local copies of it will lead to confusion. What does M-x
electric-indent-mode do when there's a buffer local value of e-i-m? If
it toggles the global binding, it will appear not to have worked in the
current buffer. If it toggles the local binding, it is no longer a
global mode. This is why I suggested extra variables to handle locality
(see below).
> But we could provide an electric-indent-local-mode, yes. Patch welcome.
> > So, make `electric-indent-mode' t by default, yet have it tempered by the
> Have any one of you tried to use Emacs with this setting? I'm not
> fundamentally opposed to changing the default setting, but just as was
> the case for font-lock-mode, transient-mark-mode, etc... we need to be
> sure it actually works well enough in "all" cases (except those cases
> where the user just doesn't like the feature and will disable it
> globally).
I think I was a bit unclear. I meant have the _variable_ e-i-m set to t
by default, but have the electricity disabled by default by the new
buffer local variable `electric-indent-enabled-flag'. But the new
variable `electric-indent-inhibit' can do this anyhow.
> But contrary to font-lock-mode, transient-mark-mode, AFAIK not many
> people have enabled this mode yet, so I'd urge you all to try it out for
> a few weeks first, to see if you like it not only in modes like c-mode
> but also everywhere else, and if there are cases where you find it
> inconvenient, report it here, so we can see what we should do about it.
As I reported in emacs-devel, I had trouble in Text Mode with e-i-m.
> > new buffer local variables `electric-indent-enabled-function' and
> The buffer-local value of electric-indent-mode is already used for
> that purpose .....
I think this is a bad thing (see above), and such uses should be
superseded by using ...
> ... (and there's also the new electric-indent-inhibit which I recently
> added, which prevents reindentation, while still doing automatic
> indentation for new lines.
Surely e-i-inhibit should be t by default. Electric indentation is
useful in (?most) programming modes, but probably not very much in text
modes, or things like Outline Mode. It is useful precisely where the
indentation of a line is determined by that same line's contents.
(That's not counting the `newline-and-indent' behaviour.) That surely
happens only in programming modes, or the like. How about having
e-i-inhibit t by default, but setting it to nil in `prog-mode'?
> Stefan
--
Alan Mackenzie (Nuremberg, Germany).
This bug report was last modified 11 years and 245 days ago.
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